Has anybody found NWS discussion on the latest model runs?
NWS CAE (Columbia)
National Weather Service Columbia SC
746 AM EST Wed Jan 21 2026
.WHAT HAS CHANGED...
Confidence continues in a potentially impactful winter storm
this weekend, with some small tweaks in the forecast thinking.
&&
.KEY MESSAGES...
- 1) The trend continues towards a potentially significant
winter storm this weekend.
- 2) After very cold start Wednesday, temps steadily moderate
through Friday along with some rain chances.
&&
.DISCUSSION...
KEY MESSAGE 1: The trend continues towards a potentially
significant winter storm this weekend.
Overview: The forecast thinking has not changed much for the weekend
system with potential for a highly impactful winter storm
continuing. The overall synoptic pattern is quite consistent across
all guidance with a deep digging
trough off the NE
CONUS,
strong
confluence and an associated strong surface high in the
central- eastern
CONUS, and an ejecting
cutoff shortwave in the
SW
CONUS. This patterns sets up a broad
overrunning scenario as
the arctic high digs southeastward presenting an all-hazards
impactful winter storm potential for much of the southern and
eastern US, including GA and SC as strong cold air damming sets
up.
Trends and Forecast Challenges: While some disagreements continue,
guidance remains in above-typical agreement over the potential
impacts from this system given the 72-96 hour window, with historic
analogs and
climatology concurring; this setup distinctly favors
mixed precip with snow-sleet-freezing rain-rain potential. A subtle
shift in some of the 18z guidance and more evident in much of the
00z guidance is a northerly shift in the axis of heaviest
qpf,
thanks to a slightly more amplified
flow and associated low pressure
development; this also pushes the surface edge of the
CAD dome
north. This trend in guidance is seemingly driven by a very
subtle slowing of Pacific
cutoff ejection and positioning of the
broad surface high; aircraft recon early Wednesday morning
should help improve this sampling, but not until the 12z
guidance. Thanks to this trend, the GEFS has steadily become
more and more of a cold- southerly outlier compared now with the
ECE, Canadian
Ensemble, and AI suite being warmer- northerly.
As noted previously, shifts in the handling of both of the low
level cold air and the Pacific
cutoff are expected as these are
two of the most notoriously difficult meteorological features
for guidance to handle. The current trends, and anticipating
typical model biases, reinforce the thinking that the I20
corridor will potentially lie along a steep
gradient zone for
qpf and therefore potential winter impacts.
Potential Impacts: A range of impacts continues to be possible from
this system, ranging from a notable
ice storm to a inconvenience-
nuisance event with a
gradient of impacts across SC and eastern GA
looking more
likely. A mix of precip-types is expected, but trends
over the last 24 hours suggest snow is less
likely for central SC
and eastern GA. Confidence remains high that much of, if not the
entire, area will see at least some wintry weather from late
Saturday-Sunday, however specific geographic impacts remains unclear.
Based on the guidance trends, confidence is increasing that the I20
corridor will lie along the
gradient of impacts; the probabilistic
WSSI for moderate impacts summarizes this well, with ~60-80%
chance north of I20 and then ~20-40% chance south of I20. While
details in the spatial impacts are still unclear, the high end
ceiling for this system remains, with notable
ice storm potential
and lingering cold weather behind the system extending impacts
in time.
Summary: Guidance remains in fairly good agreement over much of this
forecast but subtle differences result in a range of impact
potential. Confidence is already fairly high that many areas of SC
and eastern GA will see at least some winter weather this weekend
but a
gradient of impacts is
likely geographically. Unlike many
southern winter events, the
ceiling for this event is very high with
significant impact potential.
NWS GSP
Key message 3: A winter storm system is
likely to impact the area this
weekend but details regarding precipitation amounts and type remain
uncertain. Confidence continues to increase that moderate overall
winter storm impacts could lead to hazardous travel and
power
outages.
All eyes are looking at the potential weekend winter storm
forecasted to sweep across a wide swath of the south, from the
central
CONUS to the Carolinas. Confidence continues to increase
that a storm system would
likely impact the
CWA Saturday and into
Sunday. The questions remaining are exactly what kind of
precipitation falls, quantity and how these p-types impact the area.
What we know at this point is there is high confidence of a strong
and cold
air mass spilling into the central portion of the U.S. and
spreading eastward by Friday.
Moisture in the south stretches ahead
of the frontal boundary, meaning wintry precipitation forms along
this boundary. Now, this is where the uncertainty remains as there
are many factors that will change and directly influence this system
for our area. Current guidance continues to trend at a wide swath of
p-types, including snow, ice, and sleet. Let`s talk snow first.
Current guidance from a variety of models are shifting snow further
to the north, meaning at this time, the higher totals could be over
the mountains and into parts of the
NC Piedmont, along and north of
I-40.
Probability for 12" of snow or higher is 30-40%. Depending on
where the transition zone sets up will highly influence this
potential for larger snow amounts.
Now for the less thrilling part of winter: sleet and ice potential.
At this time, this appears to be the primary p-type for areas south
of I-40, including Upstate SC, northeast Georgia and into the
southern portions of the
NC Piedmont. Current trends are placing
more of the ice just to the south and sleet right in the middle,
affecting a larger chunk of the
CWA. This doesn`t
mean snow won`t
occur, but there is
likely to be a transition from snow into the
mixed precip. Current model soundings show a weak snow profile for
Saturday before an elevated warm nose develops, indicating more of a
sleet event. However, ice probabilities are still 40-50% Saturday
night into Sunday. Though it`s too earlier for deterministic
amounts, current guidance shows a 50-60% chance for ice
accumulations of 0.25" or greater essentially southward from
the
NC/SC stateline. The confidence is increasing that
warning
criteria for ice and snow will be
met this weekend. For this, a
Winter Storm
Watch for the entire area is
likely to be issued in
the coming forecast cycle.
Details will continue to be thoroughly looked over with each
forecast cycle leading up to this weekend, but preparation should
begin at this time. Regardless of the individual p-types, the
important thing to note is there will be plenty of
QPF with this
storm. Wintry precip, whether it`s ice, sleet, or snow are going to
have widespread impacts from travel constraints, air travel
disruptions and
power outages, especially in the locations where ice
occurs. Preparations should start being made for these impacts and
any disruptions to the
power grid now.